SYNTHESIS OF HYPERBRANCHED CONJUGATIVE POLY(ARYLENEETHYNYLENE)S BY ALKYNE POLYCYCLOTRIMERIZATION

A series of new hyperbranched poly(aryleneethynylene)s are synthesized by the copolycyclotrimerizations oftetraynes(Ⅰand Ⅱ)with aliphatic monoynes(A-C)catalyzed by tantalum-,niobium-,and cobalt-based catalysts.All thereactions proceed smoothly and soluble polymers of high molecular weights(M_w up to 3.8×10~4)are obtained in high yields(up to 97%).

Aliphatic Hyperbranched Poly(amido amine)s (PAMAMs): Preparation and Modification

A series of water soluble aliphatic hyperbranched poly(amido amine)s(PAMAMs) with the same or similar chemical structure of poly(amido amine) dendrimer was successfully synthesized from commercially available AB and C_n types of monomers by one-pot polymerization via the couple-monomer methodology(CMM). The AB type monomer used in this paper was methyl acrylate, and C_n monomers were multi-amino compounds such as ethylenediamine(EDA), diethylenetriamine(DETA), triethylenetetraamine(TETA), tetraethylenepentaamine(TEPA) and pentaethylenehexamine(PEHA). The reaction mechanism was investigated by means of the mass spectra of the reaction intermediates. Adjusting the feed ratio of AB to C_n, hyperbranched polymers with different terminal groups and properties were obtained. FTIR, NMR, DSC, and TGA were used to characterize the polymers. It was found that the polymers′ properties such as solubility, thermal behaviour and encapsulation capability varied with changing the feed ratio of AB to C_n. Benzoyl and palmitoyl groups were introduced into these macromolecules by acidylation to form amphiphilic hyperbranched polymers which have a high capability to encapsulate water soluble dyes such as Congo red. It is expected that the hyperbranched PAMAMs can play an important role in the industrial applications, such as coatings, cross-linking and phase-transferring agents because of their versatility and availability.

Effect of Hyperbranched Poly(amine-ester) Grafted Nano-SiO_2 on Reinforcement and Toughness of PVC

Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.

Hyperbranched Poly(amide-ester) Mildly Synthesized and Its Characterization

AB2-type-prepolymerized monomer was rapidly （2 h） prepared at room temperature （25 ℃） using commercially available maleic anhydride （MA） and diethanolamine （DEA） as raw materials. By employing toluene-p-sulfonic acid as a catalyzer, a series of hyperbranched poly（amide-ester） （HBPAE） were successfully synthesized from prepared AB2 monomer by solution condensation polymerization through ＂one-step process＂ or ＂pseudo one-step process＂ （using pentaerythritol as a center core）. The processes were carried out at high temperature of 120 ℃ for 6 h in air atmosphere （inert protection free） with reduced pressure distillation （0.08--0.096 MPa）. The results of FT-IR, UV-Vis, TGA, and intrinsic viscosity testing by Ubbelodhe viscometer showed that the prepared HBPAEs possess three-dimensional configuration with unsaturated conjugate structure, large numbers of branches and numerous terminal hydroxyl groups. These result in their low viscosity, high solubility and thermal stability.

SYNTHESIS AND CHARACTERIZATION OF HYPERBRANCHED POLY(ESTER-AMIDE)S BASED ON GALLIC ACID AND DL-2-AMINOBUTYRIC ACID

A novel AB3-type monomer was prepared from gallic acid and DL-2-aminobutyric acid, and used for the synthesis of the biocompatible hyperbranched poly(ester-amide)s by self-polycondensation. The polymers were characterized via FTIR and NMR spectroscopy and thermal analysis, and the average degree of branching of the polymers was estimated to be 0.75. The polymers with abundant acetyl end groups were found to be amorphous with lower intrinsic viscosity, better thermal stability and excellent solubility.

NOVEL HYPERBRANCHED POLY(PHENYLENE OXIDE)S WITH PHENOLIC TERMINAL GROUPS: EFFECTS OF REACTION TIME AND CORE MOLECULES ON THE MOLECULAR WEIGHT AND POLYDISPERSITY

A novel hyperbranched poly（phenylene oxide） （HPPO） with phenolic terminal groups was prepared from 4-bromo-4＇,4＂-dihydroxytriphenylmethane as AB2 monomer in dimethylsulfoxide （DMSO） via a modified Ullmann reaction. The molecular weight and polydispersity （PD） of the resulting polymers increased with increasing reaction time. In the presence of core molecules （bisphenol A and 1,3,5-trihydroxybenzene）, which have the similar molecular backbones to the reactive monomer, the molecular weight could be controlled by varying the core-to-monomer ratio. Incorporation of a very small amount of core molecules could lead to a higher molecular weight as compared with that without the addition of core molecules. However, when the core content reached certain extent, the molecular weight would decrease with the further increase in the core content. A new similar behavior of control over the PD was also obtained. The resulting polymers were characterized by ^1H-NMR, ^13C-NMR, FT-IR, and GPC.

New Phase Transfer Agent for Dye: Application for Hyperbranched Poly (ester-amine)

Hydrophilic hyperbranched poly(ester-amine) (HPEA) synthesized from diethanolamine and methyl acrylate was used as phase transfer agent for the first time to transfer methyl orange (MO) from water into chloroform. This process was quantified by UV-Vis spectra. A possible mechanism was put forward based on the formation of amphiphilic aggregates.

NOVEL HYPERBRANCHED POLY(AMINE-ESTER) FILMS: PREPARATION, CHARACTERIZATION AND PROPERTIES

Crosslinked film of hyperbranched poly（amine-ester） （HPAE） was prepared by crosslinking its terminal hydroxyl groups with glutaraldehyde （GA）. Atom force microscope （AFM） and scanning electron microscope （SEM） reveals that they have smooth surfaces, dense and homogenous matrices. It was found that the water static contact angle is smaller than 41.7°, the tensile strength is higher than 8.9 MPa, the elongation at break is higher than 5.1%, the swelling degree is higher than 42% in water, and the Bovine hemoglobin （Hb） adsorption is relatively low. These results indicate that the crosslinked HPAE films might have some potential applications in many areas.

HYPERBRANCHED AROMATIC POLYMERS OBTAINED VIA SELF-CONDENSATION

Hyperbranched aromatic polymers were prepared by Friedel-Crafts reaction with Lewis acid, AlCl3 and ZnCl2, as the catalysts. In this work, hyperbranched polybenzyl (PB) and poly(methylene)naphthalene (PN) were synthesized and characterized by H-1-NMR and GPC. In addition, their florescence properties were measured with steady-state florescence spectra in THF and ethylene dichloride. The quantum yields of polybenzyl and poly(methylene)naphthalene in ethylene dichloride are much larger than those in THE.

Facile Route to Aromatic Hyperbranched Poly(ester amines)

The aromatic hyperbranched poly（ester amines）（AHPEAs） were successfully synthesized via the mild condensation of N-4-cyanobenzyl diethanolamine hydrogenchloride as an AB2 monomer in concentrated HCI. The polymerization was monitored by FTIR to suppose the reasonable reaction mechanism. The degree of branching was determined to be 0.55 by 1H NMR with an increased conversion of up to 96%. The glass transition temperature was measured by differential scanning calorimetry to range from -19 to 15℃ The molecular weights and polydispersities were investigated by gel permeation chromatography.

Investigation on the Structure and Curing Performances of Secondary Amine Terminated Hyperbranched Poly(ester-amine)s

Three secondary amine terminated hyperbranched poly（ester-amine）s （defined as HPEA1, HPEA2 and HPEA3） were synthesized from piperazine （A2） and trimethylolpropane triacrylate （TMPTA, B3） at their molar ratios of 2.5：1, 2.25：1 and 2.0：1, respectively. The polymers were analyzed by 1H NMR, GPC, DSC and TGA. The results indicated that the ratio of secondary amine to tertiary amine and the content of secondary amine decreased, while the molecular weight, molecular weight distribution and glass transition temperature （Tg） increased from HPEA1 to HPEA3. Due to their reactive terminal groups and flexible chains, these polymers further reacted with an epoxy resin （E51） to form cured films under ambient conditions. With increasing the ratio between secondary amine groups and epoxy groups from 1：2 to 2：1, the gel content, film hardness and onset decomposing temperature of the cured samples increased. The good film performances should make the polymers as the components of non-solvent coating materials.

Novel Method of Hyperbranched Polymer Modified Nano-SiO_2-Grafting Hyperbranched Poly(amide-ester) from Nano-SiO_2 by One-Step Polycondensation

A new method of surface chemical modification of nano-SiO2 is proposed in this paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano-SiO2 reacted with AB2-type monomer （N, N-dihydroxyethyl-3-amino methyl propionate） by one-step polycondensation. And the product＇s Fourer transform infrared （FTIR） graphs and transmission electron microscopy（TEM） images proved that hyperbranched poly （amine-ester） was grafted on nano-SiO2 surface successfully. Results show that the modified nano-SiO2 exhibits excellent dispersion and stability in some solvents such as alcohol and chloroform.

Fluorinated Hyperbranched Poly(urea-urethane)s Containing Reactive Groups: Synthesis, Characterization and Application on Cotton Fabric

A series of hyperbranched poly(urea-urethane)s (HPUs) containing short fluoroalkyl chain and reactive groups (HPUFs) capable as hydrophobic and oleophobic coating materials were synthesized. The obtained polymers were characterized by FTIR(fouier transform-infrared spectroscopy), 1H NMR(nuclear magnetic resonance), 13C NMR, 19F NMR, GPC(gel permeation chromatography), TGA(thermogravimetric analyzer), and XPS(X-ray photoelectron spectroscopy) analyses. Highly hydrophobic and oleophobic cotton fabrics could be achieved from these fluorinated hyperbranched polymers by solution-immersion coating method. The static contact angles reached to 143°, 114°, and 92° for water, hexadecane, and decane, respectively. The water and oil repellency ratings were 90 and 6, respectively, and still kept 80 and 5, respectively, after 10 soaping cycles at 50℃.

Utilization of Trimethylolpropane Based Hyperbranched Poly(Amine-Ester) as New Polymeric Admixture

Hyperbranched poly(amine-ester) (HBPAE) was synthesized via pseudo-one-step process between trimethylolpropane as a core molecule and N, N-diethylol-3-amine methylpropionate as the AB2 branched monomer. The prepared polymer was analyzed by IR, GPC, 1H-NMR and thermal analysis (TGA and DSC). The performance of the polymer in cement was tested by measuring the effect of 1, 3 and 5 wt% of HBPAE solutions on the properties of Ordinary Portland Cement. Water of consistency, setting times, bulk density, apparent porosity, compressive strength and combined water content of the polymer/cement pastes were studied. The results showed that water of consistency and apparent porosity decreased while setting times, compressive strength, combined water and bulk density increased with the polymer addition.

Synthesis and application of a novel star-hyperbranched poly(acrylic acid) for improved dental restoratives

A new star-hyperbranched poly(acrylic acid) has been synthesized and incorporated into dental glassionomer cement for enhanced mechanical strengths. The effects of arm number and branching on viscosity of the polymer aqueous solution and mechanical strengths of the formed experimental cement were evaluated. It was found that the higher the arm number and the more the branching, the lower the viscosity of the polymer solution as well as the mechanical strengths of the formed cement. It was also found that the experimental cement exhibited significantly higher mechanical strengths than commercial Fuji II LC. The experimental cement was 51% in CS, 55% in compressive modulus, 118% in DTS, 82% in FS, 18% in FT and 85% in KHN higher than Fuji II LC. The experimental cement was only 6.7% of abrasive and 10% of attritional wear depths of Fuji II LC in each wear cycle. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations.

STUDY OF NANOSIZED SILICA GRAFIED WITH HYPERBRANCHED POLY(AMINE-ESTER)

A new method to chemically modify the surface of nanosized-SiO2 was studied in this paper.Nanosized-SiO2 was grafted with hyperbranched poly(amin ester)through one-spot polycondensation between AB2 monomer and active hydroxyl on silica surface in present of catalyst.Compared with the results of FTIR and TEM,it is found hyperbranched poly(amin ester)is successfully grafted on the surface of nanosized-SiO2 and the surface properties have been changed with an expected way.The results indicate that nanosized-SiO2 grafted with hyperbranched poly(amin ester)has better dispersion in the ethanol or chloroform than that unmodified.

SYNTHESIS OF POLYMERIC β-CYCLODEXTRIN SUPPORTED BY CROSSLINKED POLY(ACRYLAMIDE-co-VINYLAMINE)AND ITS CATALYSIS OF THE HYDROLYSIS OF p-NITROPHENYL ACETATE

Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.

Preparation of a novel biodegradable β-cyclodextrin-containing polymer

A novel cyclodextrin-containing polymer was prepared by graftingβ-cyclodextrin onto the backbone of poly(D,L-lactic acid)(PLA).First,mono(6-(2-aminoethyl)amino-6-deoxy)-β-cyclodextrin(β-CD-6-en)was prepared by sulfonylation and amination ofβ-cyclodextrin and modified poly(D,L-lactic acid)(MPLA)was prepared by free radical polymerization of maleic anhydride and PLA.Then,grafting ofβ-cyclodextrin derivative to MPLA backbone was carried out by N-acylation reaction of MPLA andβ-CD-6-en in dimethyl formamide.The synthetic polymer(PLA-β-CD)was characterized by FTIR(Fourier transform infrared)spectroscopy and proton nuclear magnetic resonance(1H NMR)spectroscopy.The results demonstrated that,in the context of remaining the chain structure of PLA,the content ofβ-CD-6-en is 1.6%by the developed synthetic method.

Synthesis and characterization of a novel amphiphilic biodegradable β-cyclodextrin/poly(γ-benzyl L-glutamate) copolymer

β-Cyclodextrin/poly（γ-benzyl L-glutamate） （β-CD-PBLG） copolymers were synthesized by ring-opening polymerization of N- carboxy-γ-benzyl L-glutamate anhydride （BLG-NCA） in N,N-dimethylformamide （DMF） initiated by mono-amino-β-cyclodextrin（H2N-β-CD）. The structures of the copolymers were confirmed by IR, ^1H NMR and GPC. The fluorescence technique was used to determine the critical micelle concentrations （CMC） of copolymer micell solution, the diameter and the distribution of micelles were characterized by DLS. The results showed that BLG-NCA could be initiated by H2N-β-CD to produce copolymer. The nanomicells were formed by these copolymers in water.

Synthesis and Physicochemical Characterization of Biodegradable Star-Shaped Poly Lactide-Co-Glycolide-<i>β</i>-Cyclodextrin Copolymer Nanoparticles Containing Albumin

The purposes of this research were to synthesize and characterize star-shaped poly lactide-co-glycolide-β-cyclo-dextrin (PLGA-β-CD) copolymer by reacting L-lactide, glycolide and β-cyclodextrin in the presence of stannous octoate as a catalyst. The structure of PLGA-β-CD copolymer was confirmed with 1H-NMR, 13C-NMR and FT-IR spectra. Albumin as a model peptide drug was encapsulated within nanoparticles made of PLGA-β-CD with a modified double emulsion method. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) photomicrographs showed that the nanoparticles have the mean diameter within the range of 80 - 210 nm. Also they were almost spherical in shape. Effects of the experimental parameters, such as copolymer composition, copolymer concentration, and reaction temperature, on particular size and encapsulation efficiency were investigated.